Open captions
Captions that are permanently embedded in the video frame — visible to all viewers, not toggleable.
Open captions are part of the video itself. The text is rendered into the pixels, so every viewer sees the same captions regardless of platform, device, or playback settings. This removes the dependency on a CC button working correctly across many environments.
The tradeoff is rigidity: open captions can't be turned off, can't be translated to another language without re-rendering, and can't be customized for individual viewers (font size, contrast, color).
Open captions are common in social-video platforms where autoplay is muted (Instagram, TikTok) — viewers see captions whether they wanted them or not. Live event broadcasts typically use closed captions instead, with attendee-side display preferences.